Java基于springMVC的验证码案例

```
Java验证码案例（基于springMVC方式）

验证码工具类
package com.ekyb.common.util;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;

import java.awt.image.BufferedImage;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Random;

import javax.servlet.http.HttpServletRequest;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

/**
 * 图片验证码生成类
 * 
 * @author gx
 */
@Component("imageCode")
public class ImageCode {
    /*
     * Spring 3支持@value注解的方式获取properties文件中的配置值，大简化了读取配置文件的代码。
     * 在applicationContext.xml文件中配置properties文件,在bean中使用@value注解获取配置文件的值
     * 即使给变量赋了初值也会以配置文件的值为准。
     */
    @Value("${ImageCode.width}")
    private int width;

    @Value("${ImageCode.height}")
    private int height;

    @Value("${ImageCode.codeLength}")
    private int codeLength;

    @Value("${ImageCode.randomString}")
    private String randomString;

    @Value("${ImageCode.sessionKey}")
    private String sessionKey;

    @Value("${ImageCode.font.name}")
    private String fontName;

    @Value("${ImageCode.font.style}")
    private int fontStyle;

    @Value("${ImageCode.font.size}")
    private int fontSize;

    public BufferedImage getImage(HttpServletRequest request) {
        // 在内存中创建图片
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        // 获取图片上下文
        Graphics g = image.getGraphics();
        // 生成随机类
        Random random = new Random();
        // 设定背景颜色
        g.setColor(getRandColor(100, 250));
        g.fillRect(0, 0, width, height);
        // 设定字体
        g.setFont(new Font(fontName, fontStyle, fontSize));
        g.setColor(getRandColor(160, 200));
        for (int i = 0; i < 155; i++) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(12);
            int yl = random.nextInt(12);
            g.drawLine(x, y, xl, y + yl);
        }
        // 取随机产生的认证码
        String sRand = randomRand(codeLength);
        int strWidth = width / 2 - g.getFontMetrics().stringWidth(sRand) / codeLength - fontSize;
        int strHeight = height / 2 + g.getFontMetrics().getHeight() / 4;
        for (int i = 0; i < codeLength; i++) {
            String rand = sRand.substring(i, i + 1);
            g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
            g.drawString(rand, 13 * i + 6 + strWidth, strHeight);
        }
        //System.out.println(sRand);
        request.getSession().setAttribute(sessionKey, sRand);
        request.setAttribute("sRand", sRand);
        g.dispose();
        return image;
    }

    public static String randomResult(int length) {
        String[] i = { "1", "2", "3", "4", "5", "6", "7", "8", "9", "0" };
        List<String> l = new ArrayList<String>();
        l.addAll(Arrays.asList(i));
        Random ran = new Random();
        String s = "";
        while (l.size() > 10 - length)
            s += l.remove(ran.nextInt(l.size()));
        s = s.replaceAll("^(0)(\\d)", "$2$1");
        return s;
    }

    // 给定范围获取随机颜色
    public Color getRandColor(int fc, int bc) {
        Random random = new Random();
        if(fc > 255) {
            fc = 255;
        }
        if(bc > 255) {
            bc = 255;
        }
        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);
        return new Color(r, g, b);

    }

    private String randomRand(int n) {
        String rand = "";
        int len = randomString.length() - 1;
        double r;
        for (int i = 0; i < n; i++) {
            r = ((Math.random())) * len;
            rand = rand + randomString.charAt((int) r);
        }
        return rand;
    }

    public int getWidth() {
        return width;
    }

    public void setWidth(int width) {
        this.width = width;
    }

    public int getHeight() {
        return height;
    }

    public void setHeight(int height) {
        this.height = height;
    }

    public int getCodeLength() {
        return codeLength;
    }

    public void setCodeLength(int codeLength) {
        this.codeLength = codeLength;
    }

    public String getRandomString() {
        return randomString;
    }

    public void setRandomString(String randomString) {
        this.randomString = randomString;
    }

    public String getSessionKey() {
        return sessionKey;
    }

    public void setSessionKey(String sessionKey) {
        this.sessionKey = sessionKey;
    }

    public String getFontName() {
        return fontName;
    }

    public void setFontName(String fontName) {
        this.fontName = fontName;
    }

    public int getFontStyle() {
        return fontStyle;
    }

    public void setFontStyle(int fontStyle) {
        this.fontStyle = fontStyle;
    }

    public int getFontSize() {
        return fontSize;
    }

    public void setFontSize(int fontSize) {
        this.fontSize = fontSize;
    }

}

-----------------------------------------------
读取config.properties配置的验证码和图片设置

#ImageCode生成器配置  
ImageCode.width=120  
ImageCode.height=38  
ImageCode.codeLength=4  
ImageCode.randomString=ABCDEFGHIJKLMNPQRSTUVWXYZ1234567890abcdefghijkmnpqrstuvwxyz  
ImageCode.sessionKey=SESSIONCODE  
ImageCode.font.name=Times New Roman  
ImageCode.font.style=0  
ImageCode.font.size=18 
-------------------------------------------------
springMVC action中的代码
package com.ekyb.common.auContract.action;

import java.io.IOException;

import javax.annotation.Resource;
import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import com.ekyb.common.util.ImageCode;

@Controller
@RequestMapping(value="/yanZhen")
public class YanZhenMaAction {
    /*
     * @Resource默认按 byName 自动注入,是J2EE提供的， 需导入Package: javax.annotation.Resource;
     * 
     * @Resource有两个中重要的属性：name和type ，而Spring将@Resource注解的name属性解析为bean的
     * 名字，而type属性则解析为bean的类型。所以如果使用name属性，则使用byName的自动注入策略，而使用 type属性时则使用
     * byType自动注入策略。如果既不指定name也不指定type属性，这时将通过反射机制使用by Name自动注入策略。
     */
    @Resource
    ImageCode imageCode;
    
    private static String sRand;

    @RequestMapping(value = "/openLoginPage")
    public String openLoginPage(HttpServletRequest request, HttpServletResponse response) {
        String msg=request.getParameter("msg");
        if(msg==null&& msg.isEmpty()){
            //得到用户读入框信息，如果没有输入或者为空，直接跳转到验证失败页面
            return "error";
        }else{
            if(sRand.equalsIgnoreCase((msg))){
                //得到用户输入的验证码匹配成功，跳转到验证通过页面
                return "ok";
            }else{
                //得到用户输入的验证码匹配失败，跳转到验证失败页面
                return "error";
            }
        }
    }

    @RequestMapping(value = "/getImage")
    public void getImage(HttpServletRequest request, HttpServletResponse response
            ) throws IOException {
        // 禁止图片缓存
        response.setHeader("Pragma", "no-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);
        response.setContentType("image/jpeg");
        // 将图像输出到servlet输出流中
        ServletOutputStream sos = response.getOutputStream();
        ImageIO.write(imageCode.getImage(request), "jpeg", sos);
        sos.close();
        sRand=(String)request.getAttribute("sRand");
        String result="ok";
    
    }
}
-------------------------------------------------
前端登录页面代码
<%@ page language="java" pageEncoding="utf-8"%>
<%
    String path = request.getContextPath();
    String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort() + path + "/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>登录</title>
</head>
<script type="text/javascript" src="js/jquery-easyui/jquery.min.js"></script>
<body>
    <!-- cursor: pointer;鼠标放上显示手;   title:鼠标放上时显示的文字 -->
    <img id="imageCode" alt="" src="" οnclick="checkcode()" style="cursor: pointer;" title="点我更换验证码" />
    <br>
    <form action="<%=basePath%>yanZhen/openLoginPage" method="post">
        <input type="text" value="" name="msg">
        <input type="submit" value="提交">
    </form>
</body>
<script type="text/javascript">
    var basePath = "<%=basePath%>";
    $(function() {
        checkcode();
    });
    function checkcode() {
        var XMLHttp = null;
        if (window.XMLHttpRequest) {
            XMLHttp = new XMLHttpRequest();
        } else if (window.ActiveXObject) {
            XMLHttp = new ActiveXObject("Microsoft.XMLHTTP");
        }
        XMLHttp.onreadystatechange = function() {
            if (XMLHttp.readyState == 4) {
                //改变验证码图片
                $("#imageCode").attr("src",(basePath + "/yanZhen/getImage?" + new Date()));
            }
        };
        //将请求发送出去
        //加上 new Date()防止浏览器缓存，不重新发送请求
        XMLHttp.open("GET", basePath + "/yanZhen/getImage?" + new Date(), true);
        XMLHttp.send(null);
    }
</script>
</html>
-----------------------------------------------------
登录成页面ok.jsp
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
    String path = request.getContextPath();
    String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()
            + path + "/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>验证通过</title>
</head>
<body>
    <h2>验证通过</h2>
</body>
</html>
-------------------------------------------------
登录失败页面error.jsp
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
    String path = request.getContextPath();
    String basePath = request.getScheme() + "://" + request.getServerName() + ":" + request.getServerPort()
            + path + "/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>验证失败</title>
</head>

<body>
    <h2>验证失败</h2>
</body>
</html>
--------------------
==****注意个别路径根据自己的文件路劲更改==
如果有误请多指教
```